diff --git a/README.md b/README.md
index b383af937b1450ed18c4c0f9f8d6088450dbf24c..d1c643545ba87f7c99ac0cfc8b07321abf33edb5 100644
--- a/README.md
+++ b/README.md
@@ -6,12 +6,16 @@ U.S. Geological Survey (USGS) hazard software [*nshmp-haz*][1].
 For details on the format of this model, see the *nshmp-haz*
 [user guide and implementation reference][2].
 
+For prior models, see the [USGS Seismic Hazard Maps][3] web page.
+
+DOI: <https://doi.org/10.5066/P9J1OVR6> (version [5.1.0][4])
+
 ## Site Files
 
 The `map-conus.geojson` file defines the latitude-longitude range over which the USGS computes
 maps of seismic hazard from this model. The `sites-conus.geojson` and `sites-conus.csv` files
 contain the test sites at which the USGS performs more detailed comparisons between model editions.
-See the *nshmp-haz* user guide [site specification section][3] for more details on these files.
+See the *nshmp-haz* user guide [site specification section][5] for more details on these files.
 
 ## Reference
 
@@ -19,9 +23,11 @@ Petersen, M.D, Shumway, A.M., Powers, P.M., Mueller, C.S., Moschetti, M.P., Fran
 Rezaeian, S., McNamara, D.E., Luco, N., Boyd, O.S., Rukstales, K.S., Jaiswal, K.S., Thompson, E.M.,
 Hoover, S.M., Clayton, B.S., Field, E.H., and Zeng, Y., 2020, The 2018 update of the U.S. National
 Seismic Hazard Model: Overview of model and implications, _Earthquake Spectra_, 36(1) p. 5–41,
-DOI: [10.1177/8755293019878199][4].
+DOI: [10.1177/8755293019878199][6].
 
 [1]: https://code.usgs.gov/ghsc/nshmp/nshmp-haz
 [2]: https://code.usgs.gov/ghsc/nshmp/nshmp-haz/-/blob/main/docs/README.md
-[3]: https://code.usgs.gov/ghsc/nshmp/nshmp-haz/-/blob/main/docs/pages/Site-Specification.md
-[4]: https://doi.org/10.1177/8755293019878199
+[3]: https://www.usgs.gov/programs/earthquake-hazards/seismic-hazard-maps-and-site-specific-data
+[4]: https://code.usgs.gov/ghsc/nshmp/nshms/nshm-conus/-/tags/5.1.0
+[5]: https://code.usgs.gov/ghsc/nshmp/nshmp-haz/-/blob/main/docs/pages/Site-Specification.md
+[6]: https://doi.org/10.1177/8755293019878199